package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Follow;
import com.hmdp.mapper.FollowMapper;
import com.hmdp.service.IFollowService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IUserService;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 王同学
 * @since 2023-12-22
 */
@Service
public class FollowServiceImpl extends ServiceImpl<FollowMapper, Follow> implements IFollowService {
    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private IUserService userService;
    @Override
    public Result follow(Long followUserId, Boolean isFollow) {  // 关注和取关功能的具体实现
        // 1. 获取登录用户
        Long userId = UserHolder.getUser().getId();
        String key = "follows:" + userId;
        // 1. 判断到底是关注还是取关
            if (isFollow) {
                // 2. 关注 新增数据
                Follow follow = new Follow();
                follow.setUserId(userId);
                follow.setFollowUserId(followUserId);
                boolean isSuccess = save(follow);
                if (isSuccess) {
                    // 把关注用户的id，放入redis的set集合 sadd userId followerUserId
                    stringRedisTemplate.opsForSet().add(key, followUserId.toString());
                }

            } else {
                 // 3. 取关 删除数据 删除 delete from tb_follow where user_Id = ? and follow_user_id = ?
                boolean isSuccess = remove(new QueryWrapper<Follow>().eq("user_id", userId).eq("follow_user_id", followUserId));
                if (isSuccess) {
                    // 把关注用户的id从Redis集合中移除
                    stringRedisTemplate.opsForSet().remove(key, followUserId.toString());
                }
            }

        return Result.ok();

    }

    @Override
    public Result isFollow(Long followUserId) { // 判断一个用户是否关注另一个用户
        // 1. 获取登录用户
        Long userId = UserHolder.getUser().getId();
        // 2 查询是否关注 select * from tb_follow where user_Id = ? and follow_user_id = ?
        Integer count = query().eq("user_id", userId).eq("follow_user_id", followUserId).count();
        // 3. 判断 count > 0 ? 关注 : 没关注
        return Result.ok(count > 0);
    }

    @Override
    public Result followCommons(Long id) {
        // 1. 获取当前用户
        Long userId = UserHolder.getUser().getId();
            String key = "follows:" + userId;
        System.out.println("userId1:" + userId);
        // 2. 求交集
            String key2 ="follows:" + id;
        System.out.println("userId2:" + id);
        Set<String> intersect = stringRedisTemplate.opsForSet().intersect(key, key2);
        if (intersect == null || intersect.isEmpty()) {
            return Result.ok(Collections.emptyList());
        }
        // 3. 解析id集合
        List<Long> ids = intersect.stream().map(Long::valueOf).collect(Collectors.toList());
        // 查询用户
        List<UserDTO> users = userService.listByIds(ids)
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());
        return  Result.ok(users);
    }
}
